Vehicle and vehicle control method

Abstract

Provided is a vehicle including an engine, a first MG (motor generator), a second MG, a power split device that couples them, and an ECU. ECU determines whether or not to permit execution of pressing control for suppressing idling vibrations produced by the power split device in an idling state of the engine depending on whether or not the combustion state of the engine is good, and sets a permission flag in accordance with a determination result. ECU determines whether or not the vehicle is stopping and is in the idling state. While the vehicle is stopping and is in the idling state and if the permission flag F is “ON”, ECU executes pressing control to cause the first MG to produce pressing torque Tp. If the permission flag F is “OFF”, ECU does not execute pressing control so that the first MG does not produce pressing torque Tp.

The invention claimed is: 
     
       1. A vehicle comprising:
 an internal combustion engine; 
 a first motor; 
 a second motor; 
 a driven wheel; 
 a planetary gear mechanism including a sun gear coupled to said first motor, a ring gear coupled to said second motor and coupled to said driven wheel via a reduction gear, a pinion gear engaged with said sun gear and said ring gear, and a carrier coupled to said internal combustion engine and rotatably supporting said pinion gear; and 
 a control device that controls said first motor, wherein 
 said control device determines whether or not a combustion state of said internal combustion engine is good based on whether or not a rotation speed or torque of said internal combustion engine falls below a predetermined value, 
 when said internal combustion engine is in an idling state and when a combustion state of said internal combustion engine is good, said control device causes said first motor to produce torque in a direction in which said internal combustion engine is prevented from rotating, and 
 when said internal combustion engine is in an idling state and when said combustion state is not good, said control device causes said first motor to produce a torque in the direction in which said internal combustion engine is prevented from rotating, said torque being smaller than when said combustion state is good. 
 
     
     
       2. The vehicle according to  claim 1 , wherein when said internal combustion engine is in the idling state and when said combustion state is not good, said control device does not cause said first motor to produce the torque in the direction in which said internal combustion engine is prevented from rotating. 
     
     
       3. The vehicle according to  claim 2 , wherein
 said control device determines whether or not said combustion state is good while said internal combustion engine is operating, and stores a determination result, and 
 when said internal combustion engine is in the idling state while said vehicle is stopping, said control device causes said first motor to produce the torque in the direction in which said internal combustion engine is prevented from rotating if there is no history including a determination that said combustion state is not good, and does not cause said first motor to produce the torque in the direction in which said internal combustion engine is prevented from rotating if there is a history including the determination that said combustion state is not good. 
 
     
     
       4. The vehicle according to  claim 3 , wherein if a rotation speed of said internal combustion engine does not reach a predetermined speed by the time when a predetermined time elapses after startup of said internal combustion engine, said control device determines that said combustion state is not good and stores a determination result. 
     
     
       5. The vehicle according to  claim 3 , wherein if a rotation speed of said internal combustion engine falls below a predetermined speed while said internal combustion engine is in the idling state with said motor producing no torque, said control device determines that said combustion state is not good and stores a determination result. 
     
     
       6. The vehicle according to  claim 3 , wherein if the torque of said internal combustion engine falls below predetermined torque while said internal combustion engine is in a load operating state in which torque higher than in the idling state of said internal combustion engine is output, said control device determines that said combustion state is not good and stores a determination result. 
     
     
       7. A vehicle comprising:
 an internal combustion engine; 
 a first motor; 
 a second motor; 
 a driven wheel; 
 a planetary gear mechanism including a sun gear coupled to said first motor, a ring gear coupled to said second motor and coupled to said driven wheel via a reduction gear, a pinion gear engaged with said sun gear and said ring gear, and a carrier coupled to said internal combustion engine and rotatably supporting said pinion gear; and 
 a control device that controls said first motor, wherein 
 when said internal combustion engine is in an idling state and when a reference fuel higher in volatility than a heavy fuel is used, said control device causes said first motor to produce torque in a direction in which said internal combustion engine is prevented from rotating, and 
 when said internal combustion engine is in an idling state and when said heavy fuel is used, said control device causes said first motor to produce a torque in the direction in which said internal combustion engine is prevented from rotating, said torque being smaller than when said reference fuel is used. 
 
     
     
       8. The vehicle according to  claim 7 , wherein when said internal combustion engine is in the idling state and when said heavy fuel is used, said control device does not cause said first motor to produce the torque in the direction in which said internal combustion engine is prevented from rotating.